Production of polycyclic compounds



United States Patent PRODUCTION OF POLYCYCLIC COMPOUND Lawrence G. Cannell, Lafayette, Callf., assignor to Shell Oil Company, New York, N.Y., a corporation of Delaware r No Drawing. Filed Mar. 30, 1964, Ser. No. 355,888

6 Claims. (Cl. 260-666) This invention relates to a novel class of polycyclic organic compounds and to a method for the production thereof. More particularly, it relates to novel saturated and ethylenically unsaturated bicyclo(4.2.1) hydrocarbons havinga ring system of nine carbon atoms and to methods by whi c h such polycylic compounds are produced.

It is an object of the present invention to provide a novel class of polycyclic organic compounds andmethods for the production thereof. A more particularobject is to provide novel hydrocarbons containing a bicyclo(4.2.l) carbocycli-c ring system of nine carbon atoms, which ring system is saturated or contains froin l to 3 ethylenic linkages wherein no bridgehead carbon'atom is a member of an ethylenic carbon-carbon bond. An additional object is to provide novel methods for the production of such bicycliccompounds. I

It has now been found that these objects are accomplished by processes which comprise the pyrolysis of certain classes of polycyclic compounds possessing a more complex ring system. Such' processes provide the desired ring system directly or alternatively provide precursors thereof; from which the desired'bicyclic compounds are easily produced.

The novel compounds of the invention comprise the bicyclo(4.2.l )nonanes and the corresponding-ethylenically unsaturated-bicyclic compounds having from 1 to 3 endo ethylenic linkages, i.e., non-aromatic carbon-carbon double bonds wherein both carbons are members of the carbocyclic ring system. Genetically, these compounds are nonto tri-ethylenically unsaturated bicyclo(4.'2.'l )nonanes. Although numerous positions isomers'are available when the bicycliccompound contains ethylenic linkages, preferred compounds of the invention are those nonto triethylenically unsaturated bicylco(4.2.1)nonanes wherein no bridgehead carbon atom, i.e., no carbon atom common to two or more rings, is a member of an ethylenic linkage. One class of such compounds has from 9 to 89 carbon atoms, preferably from 9'to 40,'and is represented by the formula wherein R independently is hydrocarbon containing no non-aromatic unsaturation, e.g., alkyl, cycloalkyl or aryl, having from 1 to 10 carbon atoms, preferably from 1 to 6, and m represents the number of R substitutents and is a whole number from 0 to 8 inclusive, preferably from 0 to 4. In the above-depicted formula, the dotted linedesignationis employed to indicate possible locations of ethylenic linkages. The designation, as employed herein, generical-ly signifies that the. bond between the carbon atoms connected by the dotted line may be a single bond, -i.e., a saturated carbon-carbon linkage, or alternatively may be a double bond, i.e., an ethylenic' linkage, depending, of course, on Whether the bicyclic compound is saturated or monoto tri-ethylenically unsaturated. It will heap- ,preciated that in accord with the preference for bicyclic compounds which are saturated or unsaturated with endo ethylenic linkages not involving bridgehead carbon atoms, the locations designated by .the dotted lines are'the only atoms, and from 0 to 1 additional ethylenic linkages.

3,265 ,749 Patented August 9, 1966 ice locations which may alternatively be single or double bonds. It will also be observed that the cyclic structure of the molecule precludes any single carbon atom from being a member of two ethylenic linkages, and the compounds of the invention do not contain adjacent ethylenic linkages, i.e., allene moieties. As will be shown hereinafter, by varying the substitution of R groups on reactant molecules, bicyclic compounds possessing R substituents in a variety of locations may be prepared. Preferred, however, are bicyclic compounds of the above-depicted formula wherein each carbon atom of the eight membered ring has no more than a single R substituent, and the 2 and 5 carbon atoms have only hydrogen substituents. It is to be understood that R groups, when present, replace hydrogen substituents that are present in the non-R substituted bicyclic compound, and the remaining valences of carbon atoms that are not substituted with R groups are satisfied with hydrogen substituents.

The bicyclic compounds of the invention are produced by the thermal conversion, i.e.,pyrolysis, of hydrocarbon compounds possessing a more complex ring system. Preferred compounds of this type are nonto mono-ethylenically unsaturated tricyclo(4.2.l.0 )-non-3-enes or precursors thereof. By n0nto monoethylenically unsaturated tricyclo(4.2.l.0 non-3-ene is meant a tricyclonon-3-ene incorporating the (4.2.1.0 ring system with an ethylenic linkage between the 3 and 4 carbon In accordance with the preference for bicyclic products possessingethylenic linkages not involving bridgehead carbon atoms, it is preferred that the additional ethylenic linkage, if additional ethylenic linkage is present, also not involve a bridgehead carbon atom. Preferred nonto mono-ethyl- I I I I wherein R, m and the dotted line designatioiii have the previously stated significance. y

One convenient method for preparing the nonto monoethylenically unsaturated tricyclo(4.2.l.0 )non-3-ene reactants is by condensation of an acetylenic hydrocarbon comprising a single carbon-carbon triple bond, the substituents on which are hydrogen or hydrocarbyl having from 1 to 10 carbon atoms, preferably 1 to 6, and containing no non-aromatic unsaturation, with a bicyclo (2.2.1)-hept-2-ene which alternatively may possess an additional endo ethylenic linkage not involving a bridgehead carbon atom, i.e., alternatively may be a bicyclo (2.2.1) hepta-2,5-diene. I The condensation is -effected in the presence of a transition metal, preferably nickel, complex as cat alyst, which complex contains the metal in a reduced oxidation state, preferably 0, and is stabilized by complex formation with stabilizing ligands such as phosphines, stibines, arsines, carbon monoxide and the like, but is preferably stabilized with (trihydrocarbyl)phosphite, particularly trialkylphosphites. A particularly useful catalyst for this condensation is tetrakis[tri(2-ethylhexyl)- phosphite]nickel(0). The condensation process is represented by the following equation.

preferred that the carbon atoms of at least one ethylenic The bicyclo(2.2.l)hepta-2,5-dienes are conveniently phosphite, the bicycloheptadiene dimerizes to produce prepared by condensation of a cyclopentadiene and an the pentacyclo(8.2.l.l .0 .0 )-tetradeca 5,11 diene acetylenic hydrocarbon, such ;as by the process described product. The process for this dimerization, which is in US. 2,875,256 issued Febrhary 24, 1959, to Hyman et illustrated by the following equation, is described more al. In like manner, bicyclo(2.2.l)hept-2-enes are we fully in co-pending application of Muller et al., Serial No. pared by analogous reaction of cyclopentadienes and 257,090, filed February 8, 1963. ethylenic compounds. Although the above equation represents reaction of unsubstituted bicyclic compounds and acetylene, it should be understood that the process is equally applicable to reaction of hydrocarbyl-substituted 10 compounds. For ease of condensation, however, it is While the equation illustrates the reaction of unsubstituted bicycloheptadiene, it should be understood that the bicycloheptadiene may be substituted with up to mR substituents wherein R and m have the previously stated significance. 'For ease of condensation, however, it is preferred that the carbon atoms of at least one ethylenic linkage of the bi-cycloheptadiene be substittuted with hydrogens.

The bicycloheptadiene dimer is converted to a mixture of products by pyrolysis. Without wishing to be bound by any specific theory, it appears that the initial pyrolysis products are a cyclopentadiene and a tricyclo(4.2.l.0 nona-3,7-diene, which latter compound at least in part undergoes ring opening to the bicyclic compounds of the invention, as is described hereinbefore. The products of the pyrolysis of the pentacyclo-(8.2.l.l "'.0 .0 )tetradeca-5,1l-diene therefore comprise a mixture of tricyclo- 30 (4.2.l.0 )nona 3,7 diene and bicyclo(4.2.l)nona-2,4,7-

triene in varying proportions, together with an amount of linkage of the bicyclic reactant be substituted with hydrogens, as is depicted. This production of nonto monoethylenically unsaturated tricyelo(4.2.l.0 )non 3 enes and related materials, as well as the suitable nickel catalysts, is described more fully and is claimed in copending application of L. G. Cannell, U.S. Serial No. 355,889, filed of even date.

The nonto mono ethylenically unsaturated tricyclo- (4.2.l.0 )non-3-ene is converted to the isomeric nonto mono-ethylenically unsaturated bicyclo(4.2.l)nona-2,4- diene by maintaining the tricyelic reactant at an elevated temperature. Such a thermal conversion is represented by the equation m I cyclopentadiene equimolar with the total of bicyclic wherein R, m and the dotted line designation have preand tricyclic products. This pyrolysis is represented by viously stated significance. Temperatures that are suitthe following equation H a p a a ably employed for the thermal conversion are from about wherein R and m have the previously stated significance. 200 C. to about 500 C., although pyrolysis temper- Although the pentacyclic reactant is depicted as having a atures from about 350C. to about 450 C. are preferred. planar configuration, it will be appreciated that various The thermal conversion is efiected at pressures that are cis-trans and endo-exo isomers of the pentacyclotetradecasubatmospheric, atmospheric or superatmospheric, aldiene will be formed during bicycloheptadiene dimerizathough the use of pressures other than atmospheric aption, and the ease of pyrolysis will be somewhat variable.

pears to offer little advantage, and utilization of pressures The pyrolysis is conducted at temperatures from about that are substantially atmospheric are preferred. The 200 C. to about 500 C., although temperatures from pyrolysis may be conducted in a batchwise manner as by about 250 C. to about 475 C. are preferred. The

maintaining the tricyclic reactant at or about reflux tempyrolysis is typically conducted at atmospheric or superperature and subsequently recovering the pyrolysis prodatmospheric pressures, although utilization of pressures ucts therefrom, as by distillation. It is equivalently usethat are substantially atmospheric are preferred.

ful and generally preferred to conduct the thermal con- The thermal conversion of the pentacyclotetradecaversion of tricyclic reactant in a continuous process as by diene is conducted in a batchwise manner, as by mainpassing the tricyclic reactant through a heated tube, totaining the reactant at an elevated temperature and regether with an inert carrier gas such as nitrogen, helium, moving the pyrolysis products therefrom by distillation, argon, steam and the like, and recovering the bicyclic or alternatively the pyrolysis is conducted in acontinuous product from the efiluent by conventional methods, e.g., manner as by passing the pentacyclic reactant through a fractional distillation. heated tube, preferably employing an inert carrier gas,

An alternate modification of the pyrolysis process of and recovering the desired product from the efiluent. the invention comprises the thermal conversion of a pre- The ratio of tricyclononadiene to bicyclononatriene in cursor of the nonto mono-ethylenically unsaturated trithe product mixture is determined somewhat by the pycyclo(4.2.1.0 )-non-3-ene. The preferred precursor type rolysis temperature and the residence time. At temperis a pntacyclo-(SZ.1 .0 .0 )tetradeca 5,11 diene, atures below about 300 C. and short residence times, the which may also be referred to as a bicyclo(2.2.l)heptatricyclononadiene is the predominant polycyclic product 2,5-diene dimer. Bicyclo-(Z.2.1)hepta-2,5-diene is caby a ratio of about 7:l. When higher temperatures are pable of dimerizing to produce a variety of products, deemployed, e.g., about 400 C., the bicyclononatriene is pending in part upon the reaction conditions employed. the major polycyclic product, being formed in a ratio of In the presence of certain transition metal complex catabout 3:1 to the tricyclononadiene. Upon this basis, it

alysts, particularly those complexes of nickel wherein the is considered likely that the initial pyrolysis product is metal is present in a reduced oxidation state and is comthe tricyclononatriene which undergoes more extensive plexed with stabilizing ligands such as trihydrocarbylring opening under more vigorous pyrolysis conditions.

The production of bicyclo(4.2.l)nona-2,4,7-triene from bicycloheptadiene dimer is therefore favored by higher pyrolysis temperatures and longer residence times. Good results are obtained by employing an initial pyrolysion, asby. utilizing a comparably low initial pyrolysis temperature, e.g., 200 C. to 300 C., and subsequently conducting a second thermal conversion at a higher temperature, e.g., 350 C. to 450 C., to promote more extensive. isomerization, i.e., ring opening, to the desired bicyclic nonatriene. Subsequent to the thermal conversion, the product mixture is separated and the bicyclononatriene recovered by conventional methods such as fractional distillation, selective extraction and the like.

As described above, thermal conversion of the nonto mono-ethylenically unsaturated tricyclo(4.2.1.0 )non- 3-ene'or precursor thereof results in the production of bicyclo(4.2.1)nona-2,4-dienes which may have an additional ethylenic linkage between the 7 and 8 carbon atoms, depending upon the extent of unsaturation of'the reactant. These products are readily converted to the corresponding saturated hydrocarbon, or if hydrogenation is terminated before complete saturation, to -compounds which possess a lesser degree of unsaturation. For example, a bicycl(4.2.1)nona-2,4,7-triene is typical ly converted to a mixture of predominantly 'bicyclo- (4.2 .1)nona-2,7-diene, bicyclo(4.2.1)nona-3,7-diene and bicyclo'(4.2.1)non-2-ene by incomplete hydwgflnation, and a bicyclo(4.2.l)nona-2,4-diene is typically converted to a mixture of bicyclo(4.2.l)non-2-ene and bicyclo- (4.-2.1)non-3-ene. Either reactant or any of the partial hydrogenation products may be converted to the saturated bicyclo(4.2.1) nonane by allowing hydrogenation to proceed to completion. Hydrogenation is conveniently effected by contacting the unsaturated bicyclic, compounds with molecular hydrogen in the presence of a conventional hydrogenation catalyst. Typical of such catalysts are transition metals of Group VIII of the Periodic Table, e.g., platinum, palladium and rhodium,- or oxides thereof, which may be unsupported or supported upon inert carriers such as carbon, alumina and the like, as well as mixed oxide catalysts such as copper chromite,

'I-t will be apparent from the above discussion that a variety of substituted and unsubstituted bicyclic compounds may be produced. -In the nomenclature of'such compounds, as well as the reactants employed for the production thereof, conventional numbering of the ring systems has been employed, as further illustrated by the following formula. 1

Typical products of the process of the invention, numbered according to this system, include 1-ethylbicyclo(4.2.l)nona-2,7-diene and the like.

The novel ring-unsaturated compounds of the invention are useful in a variety of applications as chemical intermediates. By employing the ethylenic linkages as reactive sites,, the compounds of the inventionmay be polymerized with reactive unsaturates to form elastomers and thermoplasties. They are useful as ligands in the production of metal complexes, as dienes or dienophiles in Diels-Alder condensations, depending upon the number and the location of the ethylenic linkages, and additionally may be epoxidized to form useful epoxy resin precursors. The unsaturated linkages may be hydrated or hydroxylated to form novel alcohols from which useful conventional derivatives may be produced. In addition,

. the saturated bicyclo(4.2.l)nonanes are useful as special solvents, and high energy fuels.

.To further illustrate the novel process of the invention and the novel products obtained thereby, the following examples are provided. It should be understood that they are not to be regarded as limitations, as the teachings thereof may be varied as will be understood by one skilled in this art.

Example I Pentacyclo(8.2.1.1 .0 .0 )tetradeca 5,11 diene (bicycloheptadiene dimer) was fed at a constant rate into a heated, glass tubular reactor with helium which served as a carrier. Within 70 minutes, 7.4 g. of bicyclo(2.2'.1)- hepta-2,5-diene dimer had been introduced. The residence time was 0.16 minute and the temperature within the tube was 400 C. The liquid product, 7.2 g., was re covered and by analysis was shown to consist of 10% by weight tricyclo(4.2.l.0 )n0na 3,7 diene, 44% by weight bicyclo(4.2.1)non- 2,4,7-triene 29% by weight cycldpentadiene and 17% by weight recovered feed.

The polycyclic products were separated by distillation under reduced pressure. Bicyclo(4.2.l)nona-2,4,7-triene, B.P. 99 C. at 106 mm., n 1.5357, was obtained as one fraction in a purity of 99% as determined by gasliquid chromatographic analysis. The molecular weight of this compound was shown by mass spectroscopy to be 1-18, and the nuclear magnetic resonance spectrum was consistent with the above formula. The bicyclo(4.2.l)- nona-2,4,7-triene is a colorless liquid and is miscible with common organic solvents.

Example 11 elfluen-t indicated the product mixture consisted of 12% by weight tricyclo(4.2.l.0- )nona 3,7 -diene, 35% by weight bicyclo(4.2.l )nona 2,4,7 triene, 26% by weight.

cyclopentadiene and 27% by weight recovered feed.

, Example III The procedure of Example I was repeated, except that a pyrolysis temperature of 525 C. was employed. The principal products obtained were allylbenzene and indene; little tricyclo(4.2.l.0 )nona-3,7-diene or bicyclo(4.2.1)- nona-2,4,7-triene were observed.

Example IV Example V 3,4-dimethyltricyclo(4.2.1.0)non-3-ene was introduced into a heated tube maintained at 500 C. at a rate sufiicient to provide a residence time of 0.19 minute.

Nitrogen was employed as a carrier gas. The feed olefin was converted to an extent of 94% to a mixture of prod- 7 ucts, 89% by weight of which was 3,4-dimethylbicyclo (4.2.l)nona-2,4-d.iene, B.P. 133 C. at 80 mm. n 1.5274. Mass spectroscopy established a molecular weight of 148 for the product. An ultraviolet spectrum (in methanol) included a maximum at 264 m which is characteristic of conjugated double bonds, and the nuclear magnetic resonance spectrum was consistent wit-h the above formula.

Example VI 'millimoles (theoretical uptake is 111 millimoles) and the product, bicyclo (4.2.l)-nonane was recovered and purified by sublimation to afford a white solid, M.P. 81 C.

Mass spectroscopy confirmed the uptake of three moles of hydrogen per mole of unsaturate, and the nuclear magnetic resonance spectrum was consistent with the above formula.

Analysis.-Calc.: C, percent wt., 87.1; H, percent wt.,

12.9. Found: C, percent wt., 87.3; H, percent wt., 12.7.

Example VII Bicyc1o(4.2.1)nona-2,4,7-triene was partially hydrogenated over a copper chromite catalyst under an initial hydrogen pressure of 400 p.s.i.g. and a temperature of 150 C. lowed to proceed until hydrogen uptakes of 1:0 and 1.6

moles of hydrogen per mole of bicyclononatriene had been reached. The three partial hydrogenation products were separated by preparative gas-liquid chromatographic techniques and'examined utilizing both chemical and physical means. In each case, retentionof the bicyclo(4.2.l) ring system was confirmed by a further experiment wherein hydrogenation over the copper chromite catalyst was allowed to proceed to completion to yield bicyclo(4.2.l)

nonane.

The mass spectra of the partial hydrogenation products allowed determination of the extent of hydrogenation from consideration of the parent ion peaks, and the nuclear magnetic resonance spectrum allowed unambiguous assignrnent of structure. The two principal products obtained in good yield from the uptake of one mole of hydrogen per mole of bicy-clononatriene were bicyclo(4.2.l)- nona-3,7-diene and bicyclo(4.2.1)nona-2,7-diene, both of which products are colorless liquids with refractive indices of u 1.5045 and n 1.5093 respectively. The principal product resulting from the uptake of two moles of hydrogen per mole of bicyclononatriene was bicyclo (4.2.1)non-2-ene, a white solid, M.P. 35 C.

I claim as my invention:

1. The process for the production of polycyclic hydrocarbon which comprises pyrolyzing tricyc1o(4.2.1.0=- non-B-ene having from 0 to 1 additional endo ethylenic In separate experiments, hydrogenation was a-llinkage connecting non-bridgehead carbon atoms, having as the only non-hydrogen ring substituents from 0 to 8 hydrocarbyl substituents independently having from 1 to 6 carbon atoms, said hydrocarbyls having only aromatic unsaturation, at a temperature from about 200 C. to about 500 C., and recovering from the resulting product mixture a bicyclo(4.2.l) hydrocarbon.

2. The process for the production of polycyclic hydrocarbon which comprises pyrolyzing tricyclo(4.2.1.0 nona-3,7-diene having from 9 to 40 carbon atoms and having as the only non-hydrogen ring substituents from 0 to 8 hydrocarbyl substituents independently having from 1 to 6 carbon atoms, said hydrocarbyls having only aromatic unsaturation, at a temperature from about 350 C. to about 450 C., and recovering from the resulting product mixture a bycyclo(4.2.1) hydrocarbon.

3. The process for the product-ion of bycyclo(4.2.1) nona-2,4,7-triene which comprises pyrolyzing tricyclo (4.2.1.0 )nona-3,7-diene at a temperature from about 350 C. to about 450 C.

4. The process for the production of bicyclo(4.2.l) nona-2,4-diene which comprises pyrolyzing tricyclo (4.2.1.0 )-non-3-ene at a temperature from about 350 C. to about 450 C.

5. The process for the production of bicyclo(4.2.l) nona-2,4,7-triene which comprises pyrolyzing pentacyclo (8.2.1.1 0 .0 )tetradeca-5,ll-diene at a temperature from about 200 C. to about 500 C. and recovering from the resulting product mixture said bicyclononatriene.

6. The process for the production of bicyclo(4.2.l) nona-2,4,7-triene which comprises initially pyrolyzing pen tacyclo(8.2.1.1 0 0 )tetradeca-5,1l-diene at a temperature from about 200 C. to about 300 C., subsequently pyrolyzing the resulting product mixture at a temperature from about 350 C. to about 450 C., and recovering from the resulting product mixture said bicyclononatriene.

References Cited by the Examiner UNITED STATES PATENTS 2,928,865 3/ 1960 Brasen 260-666 2,940,984 6/ 1960 Applequist 260666 FOREIGN PATENTS 1,035,649 8/ 1958- Germany.

OTHER REFERENCES Dr. W. Van Sanne et al., Angew. Chem., pp. 156-161, 1963.

W. Von E. Doering et al., Angew. Chem. Internat., Ed. vol. 2, No. 3, pp. -122, 1963.

Chemical Abstracts, vol. 57, Index p. 2563s, July-Dec. 1962.

DELBERT E. GANTZ, Primary Examiner.

V. OKEEFE, Assistant Examiner. 

1. THE PROCESS FOR THE PRODUCTION OF POLYCYCLIC HYDROCARBON WHICH COMPRISES PYROLYZING TRICYCLO(4.2.1.0**2,5) NON-3-ENE HAVING FROM 0 TO 1 ADDITIONAL ENDO ETHYLENIC LINKAGE CONNECTING NON-BRIGHEAD CARBON ATOMS, HAVING AS THE ONLY NON-HYDROGEN RING SUBSTITUENTS FROM 0 TO 8 HYDROCARBYL SUBSTITUENTS INDEPENDENTLY HAVIN FROM 1 TO 6 CARBON ATOMS, SAID HYDROCARBYLS HAVING ONLY AROMATIC UNSATURATION, AT A TEMPERATURE FROM ABOUT 200*C. TO ABOUT 500*C., AND RECOVERING FROM THE RESULTING PRODUCT MIXTURE A BICYCLO(4.2.1) HYDROCARBON. 